1. Field of the Invention
This invention relates to the field of processing of silver halide elements and specifically to processing fluids used therewith. Even more specifically, this invention relates to waste silver halide processing Hfluids and to the problem of waste disposal thereof.
2. Description of the Prior Art
Images formed on silver halide elements are conventionally processed by developing in fluids contained hydroquinone and other developing agents followed by so-called "fixing" the resulting image in aqueous sodium thiosulfate, for example. This last step removes all of the undeveloped silver halide and leaves the developed image areas, which are normally silver, on the element. It is conventional to process these films in automatic systems in which the developer and fixer are replenished from time to time to maintain their activity. Since the spent fixer and developer solutions have dissolved silver present, it is also conventional to recover the silver for recycle and there are a host of systems designed to accomplish this step.
After silver recovery, large amounts of aqueous wastes still remain and much of this has a small amount of dissolved silver present. Since dissolved silver is considered by some to be a hazardous waste, in many areas of the world, the user is not permitted to either ship this waste or to purge the waste into the sewers without first insuring that virtually no dissolved silver is present. Removal of these trace amounts of silver from this material is no easy task since there are so many ingredients present and these ingredients represent competing reactions which prevent silver removal. Thus, users require a large expenditure of time and money to accomplish this task.